Boiler Overhaul.

A. The flow of the combustion gas over the banks of boiler tubes is controlled by what a called baffle.

Q. What factors does baffle arrangement depends?
A.           1. Allowable draft (draught) loss
               2. The layout the boiler heating surface and its dimension
               3. Gas out position
               4. Fuel
               5. Fuel burning equipment and operating parameter
               6. Baffles supporting device

Q. What factors should be considered in designing a baffles
A. The baffle design should be such that it
              1.Ensures best distribution of heating surface with respect to gaseous product of combustion
              2. Ensures proper flue gas velocity
              3.Maintain cross flow of flue gas pass the boiler tubes
              4. Deposit flyash and dust where is it accessible for easy removal
              5. Eliminates dead pockets
              6. Avoids high draft (draught) loss

Bottom blow down valves: They provide a means for removing solid particulates that condense and lay on the bottom of a boiler. As the name implies, this valve is usually located directly on the bottom of the boiler, and is occasionally opened to use the pressure in the boiler to push these particulates out. 

Surface blow down line: It provides a means for removing foam or other lightweight non- condensible substances that tend to float on top of the water inside the boiler.